The present inventions are related to data storage, and more particularly to systems and methods for detecting contact between a sensor and a storage medium.
A read channel integrated circuit is a component of a magnetic storage device. In operation, a read channel component converts and encodes data to enable a read/write head assembly to write data to a disk and to subsequently read data back. In, for example, a hard disk drive, the disk typically includes many tracks containing encoded data that extend around the disk in a radial pattern. Each track includes one or more user data regions as well as intervening servo data regions. The information of the servo data regions is used to position the read/write head assembly in relation to the disks so that the information stored in the user data regions may be retrieved accurately.
FIG. 1 shows a storage medium 100 with two exemplary tracks 150, 155 indicated as dashed lines. The tracks are segregated by servo data written within wedges 160, 165. These wedges include data and supporting bit patterns 110 that are used for control and synchronization of the read/write head assembly over a desired location on storage medium 100. In particular, these wedges generally include a preamble pattern 152 followed by a sector address mark 154 (SAM). Sector address mark 154 is followed by a Gray code 156, and Gray code 156 is followed by burst information 158. It should be noted that while two tracks and two wedges are shown, hundreds of each would typically be included on a given storage medium. Further, it should be noted that a servo data set may have two or more fields of burst information. Between the bit patterns 110, a region of user data 184 is provided. Such user data regions 184 include various overhead and wasted areas resulting in a reduction in the density of data maintained in the region of user data 184.
Reading and writing storage medium 100 is done using a read/write head assembly (not shown) disposed in relation to storage medium 100. At times due either to anomalies on the surface of storage medium 100 or improper placement of the read/write head assembly, the read/write head assembly comes into contact with storage medium 100. This can result in damage to either the surface of storage medium 100 and/or to the read/write head assembly. Where the contact is not accurately detected, the same contact may be repeated later and/or data may be written to a damaged area of storage medium 100 resulting in a potential data loss.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for determining contact with a storage medium.